The present invention relates to a rail system of a ship for positioning and arresting a hose for supplying a fluid material to or from the ship relative to an oil rig, a method of supplying the fluid material and a ship including the rail system.
In the offshore industry, supply ships are used for the supply of materials, in particular fluid materials, i.e. liquids and or granulate material, which are flowable to an oil rig which may be a drilling oil rig, i.e. a rig on which drilling operations are performed for the discovery of oil or gas, a supply rig which supplies oil or gas to e.g. a disembarkation rig or to mainland or alternatively a hotel rig, in which personnel such as drilling workers reside. The above listing of rigs is by no means exhaustive and different or alternative kinds of rigs are contemplated to be relevant in relation to the present invention. For the supply of the fluid, i.e. liquid or granulate fluid material to the rig or receiving such materials from the rig, the supply ships are usually used, which supply ships may deliver e.g. fresh water, fuel oil, base oil, drilling water or other fluids or flowable materials needed for the operation of the rig. Alternatively, the supply ship may in accordance with the teachings of the present invention receive fluids, in particular waste material such as waste oil or waste water from the oil rig, or even oil produced by the oil rig.
The transfer of fluid to and from the oil rig to the supply ship is usually carried out by the use of fairly large hoses through which the relevant material is pumped, and for handling the one or more hoses, one or more cranes located on the oil rig and/or on the ship are used for shifting the hose or hoses between the oil rig and the ship and also positioning the hose properly in an operational position allowing the fluid material or the fluid materials to be pumped through the hose. Techniques of handling hoses of this kind have been described in patent publications in among others DE 202 16 616 U1, U.S. Pat. No. 4,867,211, U.S. Pat. No. 7,484,574, U.S. Pat. No. 7,628,172, EP 2 239 190, GB 1 581 326 and WO 2007/029999, and the latter US patent describes a hose connection device. The assignee in the latter US patent has developed a hose handling technique involving highly elaborated hose handling and fixation techniques involving the use of hydraulically operated cylinders for the locking and fixation of the hose relative to the supply ship. The hose handling techniques developed by the above assignee company, i.e. the Norwegian company ODIM ABCS, is described in a paper presented at a North Sea crane conference in 2007.
A further problem in relation to the handling and operation of hoses interconnecting an oil rig and a supply ship relates to a safety consideration, since a wave may cause the supply ship to be shifted relative to the oil rig from its operational position, which may cause excessive loads to the hoses provided the hoses are not allowed to be disconnected from the supply ship and the excessive loading of hoses may even cause a safety to the personnel operating the oil rig and/or the supply ship.